Micro-Total analysis systems or lab-on-a-chip systems, in which a microfluidic device attracts more attention, are expected to be widely used in the medical examination and diagnosis field. In the microfluidic device, it is necessary to pump and direct fluids at very small length scale, and the fluids may be pumped and directed using a mechanical approach or a non-mechanical approach.
Alex Terray et al. in an article entitled “microfluidic control using colloidal devices,” Science 7 Jun. 2002: Vol. 296, Issue 5574, pp. 1841-1844, describe that micrometer-scale fluid pumps and particulate valves are created by manipulating colloidal microspheres within customized channels.
Li Zhang et al. in an article entitled “Controlled Propulsion and Cargo Transport of Rotating Nickel Nanowires near a Patterned Solid Surface,” ACS NANO, 2010, vol. 4, no. 10, describe that rotating Ni nanowires are capable of propulsion and transport of colloidal cargo and the motion of the Ni nanowires can be precisely controlled using a uniform rotating magnetic field.
Furthermore, movement of magnetic beads under a magnetic field is discussed in the following articles: (1) He-Ching Lin et al., “Structural instability of an oscillating superparamagnetic micro-bead chain,” Microfluid Nanofluid (2014) 17:73-84; (2) Tamal Roy et al., “Magnetic microsphere-based mixers for microdroplets,” PHYSICS OF FLUIDS 21, 027101 2009; and (3) Y. Gao et al., “Numerical and experimental study of a rotating magnetic particle chain in a viscous fluid,” PHYSICAL REVIEW E 86, 041503 (2012).
U.S. Pat. No. 8,651,113 discloses a method for delivering a therapeutic to target cells within a body using a controllable magnetic field generator. The therapeutic is contained in magnetically responsive therapeutic constructs.